Sinker assist devices for knitting machines



p 22, 1964 L. MISHCON 3,149,483

SINKER ASSIST DEVICES FOR KNITTING MACHINES Filed Oct. 29, 1962 Fig. 2

INVENTOR. BY LESTER MIStHCON 35 Fig.3. 25 24 442* H ATTORNEY United States Patent 3,149,483 SEPIKER ASSET DEVECES FOR KNITTING MACHZNES Lester Mishcon, Miami Beach, Fla, assignor, by mesne assignments, to The Singer Company, New York, N.Y., a 'corporan'on of New Jersey Filed Oct. 29, 1962, Ser. No. 233,555 4 Claims. .(Cl. 66-107) This invention relates to knitting machines and more particularly to a sinker-top, latch needle knitting machine.

It is an object of this invention to provide a sinker assist device cooperating with hold-down type sinkers of a knitting machine and enabling the sinkers to function with a minimum of endwise motion.

A further object of this invention is to provide a sinker assist device disposed for accommodation within the til-oats of the hold-down type sinkers to constrain the sinker loops within the throats and to prevent flagging of the sinker loops within the throats.

With the above and additional objects and advantages in view as will hereinafter appear this invention will be described with regard to the accompanying drawings of a preferred embodiment in which:

FIG. 1 represents a top plan view of a portion of a circular knitting machine in which a portion of the yarn carrier has been broken away better to illustrate the sinker assist device of this invention applied thereto;

FIG. 2 is a cross sectional view taken substantially along line 22 of FIG. 1 illustrating portions of a needle, a sinker and the siriker assist device and showing the dis position of the parts and yarns as the needle descends; and

FIG. 3 is an enlarged cross sectional view taken substantially along line 3-3 of FIG. 1 showing the disposition of the parts and yarns as the needle rises.

Referring to the drawings, 11 indicates a needle cylinder of a circular knitting machine of which the outer surface is formed with a series of parallel vertical needle accommodating slots 12 perferably defined by thin dividing ribs 13 set into the cylinder. The cylinder may be turned carrying with it latch needles 14 constrained one in each of the slots 12. The latch needles are each formed with a yarn engaging hook 15 beneath which is pivoted a latch spoon 16. When each needle is raised, for instance by cams (not shown), the hook 15 is elevated and if elevated sufficiently will take a yarn from a yarn carrier 17. Similarly, the latch spoon 16 is moved upwardly through the previous yarn loop on the needle. This upward motion of the needles is critical since if the motion is suflicient for the latch spoon to clear the previous loop and for the hook to engage a fed yarn the needle will subsequently produce a knitted stitch. However, if the latch spoon does not clear the previous yarn loop on the needle, a tuck or a welt will result. FIG. 3 illustrates the needle as it is being raised. In making a knitted stitch, as the needle is subsequently drawn downwardly after having engaged a fed yarn from the yarn carrier in the book 15, the previous yarn loop on the needle will close the latch spoon 16 and pass or be knocked over the hook and the fed yarn carried thereby as illustrated in FIG. 2.

Disposed outwardly adjacent to the top of the needle cylinder 11, is a stationary carrier ring on which the yarn carriers 17 are secured as by bolts 21. The carrier ring 20 also has secured thereto a sinker cam ring 22 to which sinker cams 23 are secured.

A sinker rest ring 24 adapted to mesh with the needle slots 12 on the cylinder so as to turn with the cylinder is constrained rotatably relatively to the sinker cam ring 22 by means of a support ring 25 secured beneath the sinker cam ring.

The sinker rest ring is formed with upwardly open radial slots 26 each adapted to accommodate a hold-down "ice type sinker 27 for endwise sliding movement radially of the cylinder. The sinkers are further supported in a platen ring 28 fast atop the cylinder 11 which platen ring may be formed with upwardly open radial slots 29 aligned with the sinker rest ring slots 26 to guide the sinkers.

Each sinker 27 is preferably formed with a blade 30 having a straight under edge 31 adapted to bear against the platen ring 23 on the needle cylinder, and a web supporting upper edge 32. A nose 33 extends from the sinker body portion and overhangs the web supporting upper edge to define therewith a web accommodating throat 34. Extending from the sinker body portion is a shank portion 35 slidably accommodated in one of the sinker rest ring slots 26 and formed with an upstanding butt 36 which together with the sinker body portion embraces the sinker cams 23.

The sinker cams reciprocate the sinkers in timed relation with the endwise movements of the adjacent needles, moving the sinkers radially outwardly when the adjacent needles are drawn downwardly, as illustrated in FIG. 2, so that the fed yarn is deposited on the web-supporting edge 32 of the sinker. The sinkers are moved radially inwardly as the adjacent needles are raised, as illustrated in FIG. 3, so that the yarn limbs joining the previous loops on the needles will be accommodated in the sinker throats 34 and prevented by the noses 33 from rising with the needles.

It is desirable in the design of circular knitting machines that the amplitude of needle and sinker reciprocation be made as small as is possible. Aside from a consequent reduction in effort required to operate the machine, other cogent reasons for minimizing needle and sinker displace ment include reduction in tensile stresses and reduction in abrasion to the yarns and the knit fabric by the action of these parts.

There are, however, factors which dictate the minimum amplitudes of sinkers and needles. For instance, with hold-down type sinkers as above described, the outward motion must be sufficient for the sinker nose 33 to clear the fed yarn on the adjacent needle down stroke, and the inward motion must be suflicient for the sinker nose 33 to overlie and hold the yarn loop on the adjacent needles from raising on the needle upstroke.

The present invention provides a means for considerably reducing the amplitude of sinker reciprocation by the provision of a sinker assist member indicated generally at 40 in the drawing.

The sinker assist member 40 comprises a support bracket 41 which is secured by a fastening screw 42 to the sink er cam ring 22 or may also be secured in like fashion to the carrier ring 20. From the bracket 41 extends an arched arm 43 which extends over the needles and sinker noses and terminates in a blade 44 extending from the arched arm 43 in the direction of motion of the needle cylinder and spanning a plurality of the sinkers. The blade 44 is spaced uniformly above the web supporting edges 32 of the sinkers sufiiciently to accommodate snugly the web of knitted fabric produced by the machine. The outer edge 45 of the blade 44 contiguous to the needles may be formed straight and disposed substantially along a chord within the circular bank of needles 14, or may be arcuate to correspond with the curvature of the needle bank, Preferably the arched arm 43 is positioned relative to the needles and sinkers substantially at the point of maximum draw or point of lowest reciprocation of the needles after each yarn feeding station, and the blade 44 is preferably made a length equal to approximately half the peripheral distance between yarn feeding stations about the needle cylinder.

The web of knit fabric produced on the knitting machine is directed beneath the blade 44- as illustrated in FIG. 2, and on the radially inward motion of the sinkers 3 during needle rise as shown in FIG. 3, the outer edge 45 of the blade 44 will be positioned in the mouth of the sinker throat 34, that is, between the sinker nose 3?: and the Web supporting edge 32 of the sinker so as to trap and constrain in the sinker throat those yarn limbs extending between the stitch loops n the adjacent knitting needles. As a consequence, far less inward motion of the sinkers is necessary to ensure that the yarn loops will not slip past the sinker nose and rise with the needles.

The sinker assist member 40, furthermore, provides for an advantageous reduction in the amplitude of needle reciprocation. This results from the fact that the blade 44 of the sinker assist member constrains the web of knitting fabric snuggly against the web supporting edges 32 of the sinker blades and in so doing reduces the flagging of the previous yarn loops on the needles. Flagging of the yarn loops on the needles in a conventional sinker top knitting machine may vary with the type of yarn used and the knitting conditions such as web tension, stitch length and the like. The differential in needle elevation required to efiect an unquestionable difference in yarn concatenation, as for instance, as between knitting and tucking, must be at least as great as the maximum flagging of the previous yarn loop on the needle. The greater the flagging the larger must be the differential in needle elevation to ensure the formation of each type of stitch and, therefore, the greater must be the overall amplitude of needle reciprocation.

If the sinker throat 34 is narrowed to reduce flagging, the versatility of the knitting machine is curtailed because the sinker noses would interfere with webs of bulkier knits or heavier yarns. The sinker assist device of this invention makes possible the provision of an amply wide sinker throat 34 which does not limit the versatility of the machine and yet the device of this invention serves to constrain the web of knit fabric so as to minimize flagging of the yarn loops on the needles. As a result, a knitting machine equipped with the present invention provides for greater differential between the different needle elevations required to provide the various effects in knit fabric such as knitting tucking or welting. Consequently, a machine fitted in accordance with this invention will operate successfully with a wider choice of yarns, a wider variation in stitch length and in the production of a more varied range of design and stitch constructions.

Having thus set forth the nature of the invention, what is claimed herein is:

1. In a knitting machine having a bank of alternate latch needles and hold-down type sinkers each being endwise reciprocable, said sinkers transversely of said needles, each sinker being formed with a web supporting edge and a nose projecting from said sinker in spaced relation to said Web supporting edge to define therewith a web accommodating throat, a sinker assist device comprising a blade, means supporting said blade spanning a plurality of said sinkers in a spaced relation to the web supporting edges thereof a distance substantially equal to the thickness of the Web of knit fabric to be produced on the knitting machine, said blade being formed with an edge facing said sinker noses and disposed with said sinker throats upon reciprocation of said sinkers toward said A blade and beyond said sinker throats upon reciprocation of said sinkers in the opposite direction.

2. In a knitting machine having a bank of parallel circularly arranged endwise reciprocable latch needles, a circularly arranged bank of like sinkers interdigitated alternately with said needles and endwise reciprocable radially of said circular bank of needles, each of said sinkers being formed with a web supporting edge and a nose projecting radially inwardly from said sinker in spaced relation to said web supporting edge to define therewith a web accommodating throat, a sinker assist device comprising a blade, means supporting said blade within said bank of needles and spanning a plurality of said sinkers in uniformly spaced relation to the web supporting edges thereof, said blade being formed with an edge contiguous to said circular bank of needles, said edge being disposed so as to. occupy a position within said sinker throats upon radially inward reciprocation of said plurality of sinkers spanned by said blade.

3. In a multiple feed sinker-top circular knitting machine having a circularly arranged bank of alternate sinkers and endwise reciprocating knitting needles and in which each sinker is formed with a yarn hold-down nose of which the free extremity is reciprocable transversely across the circular bank of knitting needles at each yarn feed, means for assisting the operation of said sinkers comprising a sinker assist member corresponding to each feed of said knitting machine, means for supporting each sinker assist member within the circular bank of knitting needles and extending substantially from the point of maximum draw of the knitting needles trailing each feed a portion of the distance to the succeeding feed, said sinker assist members being disposed underlying said sinker nose extremities upon inward reciprocation of said sinkers to constrain yarn loops from each preceding feed beneath the sinker noses.

4. In a circular sinker-top knitting machine having a rotatable needle cylinder, a stationary carrier ring surrounding said cylinder, a sinker rest ring rotatable with said cylinder and journaled in said carrier ring a bank of knitting needles endwise reciprocable in said cylinder and a cooperating bank of sinkers endwise reciprocable in said sinker rest ring and interdigitated with said knitting needles, said sinkers each being formed with a web supporting edge and a nose projecting from said sinker in spaced relation to said web-supporting edge to define therewith a web accommodating throat, a sinker assist device comprising a bracket, means for securing said bracket relatively to said carrier ring, an arched arm on said bracket extending over said cylinder, a sinker assist blade extending from said arched arm within said bank of knitting needles, and spanning a plurality of said sinkers in uniformly spaced relation to the web supporting edges thereof, and means on said blade occupying a position within said sinker throats upon reciprocation of said sinkers inwardly of said bank of knitting needles.

References Cited in the file of this patent UNITED STATES PATENTS 

1. IN A KNITTING MACHINE HAVING A BANK OF ALTERNATE LATCH NEEDLES AND HOLD-DOWN TYPE SINKERS EACH BEING ENDWISE RECIPROCABLE, SAID SINKERS TRANSVERSELY OF SAID NEEDLES, EACH SINKER BEING FORMED WITH A WEB SUPPORTING EDGE AND A NOSE PROJECTING FROM SAID SINKER IN SPACED RELATION TO SAID WEB SUPPORTING EDGE TO DEFINE THEREWITH A WEB ACCOMMODATING THROAT, A SINKER ASSIST DEVICE COMPRISING A BLADE, MEANS SUPPORTING SAID BLADE SPANNING A PLURALITY OF SAID SINKERS IN A SPACED RELATION TO THE WEB SUPPORTING EDGES THEREOF A DISTANCE SUBSTANTIALLY EQUAL TO THE THICKNESS OF THE WEB OF KNIT FABRIC TO BE PRODUCED ON THE KNITTING MACHINE, SAID BLADE BEING FORMED WITH AN EDGE FACING SAID SINKER NOSES AND DISPOSED WITH SAID SINKER THROATS UPON RECIPROCATION OF SAID SINKERS TOWARD SAID BLADE AND BEYOND SAID SINKER THROATS UPON RECIPROCATION OF SAID SINKERS IN THE OPPOSITE DIRECTION. 